Index: includes/path.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/path.inc,v
retrieving revision 1.13
diff -u -r1.13 path.inc
--- includes/path.inc	23 Dec 2006 22:04:52 -0000	1.13
+++ includes/path.inc	13 Jan 2007 21:58:16 -0000
@@ -52,14 +52,30 @@
   if ($action == 'wipe') {
     $map = array();
     $no_src = array();
+    dmemcache_flush('alias');
+    dmemcache_flush('src');
   }
   elseif ($count > 0 && $path != '') {
     if ($action == 'alias') {
+      // static cache
       if (isset($map[$path])) {
         return $map[$path];
       }
+      // memcache
+      if ($alias = dmemcache_get($path, 'alias')) {
+        $map[$path] = $alias['value'];
+        return $alias['value'];
+      }
+      // database
       $alias = db_result(db_query("SELECT dst FROM {url_alias} WHERE src = '%s'", $path));
       $map[$path] = $alias;
+      if (!$alias) {
+        $mc_value = array('value' => $alias);
+        dmemcache_set($path, $mc_value, 300, 'alias');
+      }
+      else {
+        dmemcache_set($path, array('value' => $alias), 300, 'alias');
+      }
       return $alias;
     }
     // Check $no_src for this $path in case we've already determined that there
@@ -67,9 +83,14 @@
     elseif ($action == 'source' && !isset($no_src[$path])) {
       // Look for the value $path within the cached $map
       if (!$src = array_search($path, $map)) {
-        if ($src = db_result(db_query("SELECT src FROM {url_alias} WHERE dst = '%s'", $path))) {
+        if ($mc_src = dmemcache_get($path, 'src')) {
+          $src = $mc_src['value'];
           $map[$src] = $path;
         }
+        else if ($src = db_result(db_query("SELECT src FROM {url_alias} WHERE dst = '%s'", $path))) {
+          $map[$src] = $path;
+          dmemcache_set($path, array('value' => $src), 300, 'src');
+        }
         else {
           // We can't record anything into $map because we do not have a valid
           // index and there is no need because we have not learned anything
@@ -77,6 +98,7 @@
           $no_src[$path] = TRUE;
         }
       }
+
       return $src;
     }
   }
Index: modules/path/path.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/path/path.module,v
retrieving revision 1.105
diff -u -r1.105 path.module
--- modules/path/path.module	9 Jan 2007 08:34:03 -0000	1.105
+++ modules/path/path.module	13 Jan 2007 21:58:16 -0000
@@ -118,6 +118,8 @@
  * Post-confirmation; delete an URL alias.
  */
 function path_admin_delete($pid = 0) {
+  dmemcache_flush('src');
+  dmemcache_flush('alias');
   db_query('DELETE FROM {url_alias} WHERE pid = %d', $pid);
   drupal_set_message(t('The alias has been deleted.'));
 }
@@ -128,6 +130,9 @@
  * Set an aliased path for a given Drupal path, preventing duplicates.
  */
 function path_set_alias($path = NULL, $alias = NULL, $pid = NULL) {
+  dmemcache_flush('src');
+  dmemcache_flush('alias');
+
   if ($path && !$alias) {
     db_query("DELETE FROM {url_alias} WHERE src = '%s'", $path);
     drupal_clear_path_cache();